Calculate Speed and Determine Required Thrust

Speed vs Thrust

  • Speed is how fast something is moving. For a trolling motor speed determined by a factor of prop pitch and motor RPM
  • Thrust is simply a static measurement of pushing or pulling power, and higher thrust does not necessarily mean greater speed.

Calculate MPH

Given motor RPM under load, and Minn Kota’s 4" prop pitch, the approximate speed that a motor will push/pull a small boat can be calculated with the formula:
prop pitch in inches, times motor RPM, times 85%, (factor for prop slippage), yields calculated inches per minute. This value divided by 12 equals calculated feet per minute. The feet per minute times 60 equals calculated feet per hour. The feet per hour divided by 5280, (number of feet in a mile), equals the calculated miles per hour.
Example: ((4 x 1540 x .85) / 12) x (60 / 5280) = M.P.H.

For more information, click here to download our Runtime, Speed, and Horsepower Formulas Chart.

Determine Thrust Requirements for your Boat

Thrust requirements are determined by the size and weight of your boat. We suggest selecting a trolling motor with at least 2 lbs of thrust for every 100 lbs of boat weight when fully loaded. This guide is established under normal lake fishing conditions. If you frequently fish in heavy winds, rivers or adverse weather conditions you may want to consider a higher thrust electric motor.
Example: 2,000lb boat = (2000lb / 100) x 2 = 40lbs of thrust (minimum)Thrust.png

Rigging Guides

Click here for more information and downloadable Rigging Guides.

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